Control mechanism for refrigerators



y 1941. v s. w. E. ANDERSSON v 2,241,571

CONTROL MECHANISM FOR REFRIGERATORS Original Filed June 1, 1934 5 Sheets-Sheet 1 7(4) ATTORNEY.

May 13, 1941.

S. W. E. ANDERSSON CONTROL MECHANISM FOR REFRIGERATORS Original Filed June '1, 1934 5 Sheets-Sheet 2 INVENTOR.

May 13, 1941. s. w. E. ANDERS SON CONTROL MECHANISM FOR REFRIGERATORS Original Filed June 1, 1954 5 Sheets-Sheet 4 INVENTOR.

21 ATTORNEY.

May 13, 1941. s. w. E. ANDERSSON 1, v CONTROL MECHANISM FOR REFRIGERATQRS I Original Filed June 1, 1934 5 Sheets-Sheet 5 automatically upon melting of frost.

Patented May 13, 1941 CONTROL MECHANISM FOR REFRIGER- ATORS Sven W. E. Andersson, Evansville, Ind., assignor to Servel, Inc., New York, N. Y., a corporation of Delaware Original application June 1, 1934, Serial No. 728,525, now Patent No. 2,123,920, dated July 19, 1938. Divided and this-application March 8, 1938, Serial No. 194,593

9 Claims.

My invention relates to a control mechanism for refrigerators.

It is an object of the invention to provide a control device which may be remotely operated, for instance, from a point adjacent a-cooling element within a storage compartment of a refrigerator. Another object is to provide a control device whereby a refrigerator can be defrosted at will and the defrosting period is terminated It is a further object to provide suchhdlivice in combination with a temperature control means for a refrigerator utilizing a minimum number of parts. p

This application is a division of my copending application Serial No. 728,525, filed June 1, 1934,

now Patent No. 2,123,920, granted July 19, 1938.

In the drawings:

Fig. 1 is a broken view in front elevation of a refrigerator showing the cooling element and a control device contemplated by my invention;

' Fig. 2 is a side view partly in vertical section of the arrangement shown in Fig. 1;

Fig. 3 is an enlarged rear end view f.-the interior of the control device shown in Figs. 1 and 2; a

Fig. 4 is a section of the control device on line 4-4 in Fig. 3;

Fig. 5 is a front end view of the housing of the control device;

Fig. 6 is a section taken on line 6-6 in Fig. 5;

Fig. 7 is a partial view of the device similar to Fig. 4, illustrating a modification of the invention; and

Fig. 8 is a view similar to Fig. 1 illustrating another modification of the invention.

Referring to Figs. 1 and 2 of the drawings, a refrigerator cabinet l0, shown schematically in broken view, is of a type well known in the art,

' comprising an upper heat insulated chamber or food storage compartment ll, accessible by means of an insulated door l2, and a lower apparatus compartment 13, from which a passage It extends upwardly at the back of the refrigerator in the rear of the insulated storage compartment II. In the cabinet is mounted an'absorption refrigeration apparatus of the pressure equalized continuous type which itself is well known in the art and needs no further description here. Briefly, however, such apparatus comprises essentially an'evaporator or cooling element in which refrigerant fluid, such as ammonia, evaporates by diffusion into an inert pressure equalizing gas, such as hydrogen. The resulting gas mixture flows into an absorber where the refrigerant is absorbed by a suitable liquid absorbent such as water. The inert gas returns to the evaporator and the enriched absorption liquid is conducted to a generator. In the latter, the refrigerant is expelled from solution by heating and the weakened absorption liquid is again conducted through the absorber. The expelled refrigerant is condensed and returned to the evaporator, thus completing the cycle. The generatormay be heatedby any suitable means such as a gas burner. 1

Referring again to Figs. 1 and 2, the apparatus, of which only the parts necessary for this description are shown, is mounted in the cabinet with the evaporator l5 located in the storage compartment H and the generator l6 located principally in the lower apparatus compartment l3. The other parts of the apparatus are located eitherin the apparatus compartment [3 or the 20' vertical passage ll. The generator I6 is provided with a flue I1 and is heated by a gas burner l8 directed into the lower end of the flue as best I8 from conduit l9 through a gas filter 20 and a control device 21 respectively,

The control device 2l, shown in detail in Figs.

3 to 6, comprises an annular casing or housing consisting of an annular body member 22, a front cover plate 23, and a rear cover plate 24, the cover plates being circular and secured to the body member 22 by screws 25, or other suitable means. The interior of the body member 22 is divided by a partition 26 having a central boss 21 through which is drilled a valve opening 28. Extending through the latter is a stem or valve lifter 29 provided at one end with a valve member 30 in the upper valve chamber 3|. The valve member 30, is adapted to seat on the boss 21 to close the valve opening 28. The valve member 30 is biased to its closed position by a suitable leaf spring 32 having one end overlying the valve member and the other end secured by screws 33 to the partition 26. In the valve chamber 34 on the other side of the partition 26 there is located the expansible diaphragm or element 35 ofan expansible fluid thermostat. The expansible element 35 is mounted on a resilient diaphragm 36 which is secured at its edge with suitable gaskets between the body member 22 and cover plate 23, thus sealing the valve chamber 34. The expansible element 35 is connected by a capillary tube 31 to a sensitive bulb 38 located in thermal transfer relation with the evaporator 15, asis shown in Figs. 1 and 2. The sensitive bulb 38, capillary tube 31, and expansible element 35 are charged with a suitable temperature sensitive fluid as well known in the art, and the expansible element 35 is located in operative relation with the valve stem 29, whereby movement of the expansible element 35 responsive to variation in temperature of the evaporator |5 is transmitted by the valve stem 29 to the valve member 33 to control the valve passage 26. The body member 22 is provided with an external boss 39 drilled for passage of gas therethrough into the valve chamber 34 and tapped for gas pipe connection from the gas filter 29 if the latter is employed,

Referring again more particularly to Figs. 3 and 4, there is provided in the upper valve chamber 3| a bracket 56 which is substantially a channel member comprising side walls 59 upor direct connection to the gas supply line i9. A

second external boss 49 is drilled for passage of gas from the other valve chamber 3|, as more fully described hereinafter, and is tapped for gas pipe connection to the burner i6. Thus the flow of gas to the burner I3 is controlled by valve member 36 which is operated by the expansible element 35 in accordance with the temperature of the evaporator l5.

The cover plate 23 is provided centrally with an inset bushing 4| which is internally threaded to receive in threaded engagement an adjusting assembly comprising a sleeve 42, a pin 43, a cap member 44 and retaining nut 45. The pin 43 is provided near one end with a circular flange 46 so that when the pin 43, sleeve 42, and cap 44 are assembled they are secured togetheras a unit by the retaining nut 45 which is threaded on the other end of the pin 43 and tightened down against the cap 44. The end of the pin 43 be- ,yond the flange 46 forms an abutment for a member 41. The latter extends centrally through the resilient diaphragm 36 and is secured thereto by a retaining nut 48, thus forming the means by which the expansible element 35 is mounted on the resilient diaphragm 36 and also the means by which the capillary tube 31 is connected to the expansible element, the passage 49 through the member 41 serving this purpose. On the cap member 44 of the adjustment assembly, a grooved pulley 50 is mounted and secured by a set screw 5|, or other suitable device. Rotation of the pulley 50 moves the pin 43 on account of the threaded engagement of the sleeve 42 with the fixed cover plate 23, thereby varying the abutment of member 41 on the end of pin 43 to effect the adjustment or setting or the thermostatically operated valve previously described. It will be understood that the pulley 59 may be replaced by a control knob or dial. However, in the arrangement illustrated it is preferable to have the control knob in the upper part of the refrigerator cabinet on the front of the evaporator, as is shown in Figs. 1 and 2. The adjusting knob 52 is provided with a suitable fixed dial or index plate 53 and is mounted on the end of a rod 54 which extends from the front of the evaporator |5 through the rear wall of the storage compartment into the vertical passage l4 where'it is provided with a grooved pulley 55 similar to the pulley 50 on the control device 2|. These pulleys are operatively connected by a flexible wire belt 56 provided with a guide casing 51. Turning the knob 52 on the front of the evaporator I5 causes rotation of rod 54, pulley 55, and pulley 50, whereby the adjustment of the control thermostat is varied as previously described. For a purpose which will hereinafter appear, the arrangement just described is so constructed that only a half turn of the control adjustment knob 52 and the parts operated thereby is utilized to obtain full range adjustment of the thermostat.

turned from a flat bottom 63. An opening in the bottom 66 of the bracket 58 allows the latter to fit around the central valve boss 21 and the bracket is secured in place on three bosses formed on the partition 26, by tabs 6|, 6| and 6!" which extend from the side walls 59 of the bracket and are fastened by screws 62, 62' and 62". On a pin 63 carried by the bracket 58 is pivoted a valve lever 64 having at one end a valve member 65. A boss 66 on the partition 26 is drilled to form a valve opening 61 and the boss 66 is machined to form a seat for the valve member 65 so that the latter may control flow of gas through the valve opening 61. The latter communicates with a passage 68 which extends through the external boss 43 for passage of gas from the valve chamber 3| to the gas burner It as previously described. The valve member 65 and valve lever 64 are biased to the valve closing position by a U-shaped leaf spring 69, the ends of which may be secured by the same screws 62 and 62' which secure the bracket 58 in place as previously described. On another pin 10, carried by the bracket 58, is pivoted a lever 1| having a projection 12 at one end and a catch 13 at the other end, which catch may be formed by striking out a portion of the lever. This lever comprisesa trigger and is tensioned by a spring 14 coiled around the pin 10. The valve closing spring 32 is provided with a downturned tab 15, in which tab is a slot which receives the projecting end 12 of the trigger 1|. It will now be understood that the catch 130i the trigger 1| normally engages the end of valve lever 64 to retain the valve member 65 in its open position against the action of the U-shaped spring 69. The engagement of the tab 15 with the end 12 of trigger 1| is such that the trigger 1| will not be tripped to release lever 64 during normal operation of the control valve member 30 and the latter must be moved beyond its fully open position for the tab 15 of the valve spring 32 to lift the end 12 of the trigger 1| against the action of the coiled trigger spring 14. i

In order to move the control valve member 30 and the valve spring 32 through an abnormal distance, the previously described pin 43 of the temperature control adjustment is provided with a. ridge 16 which cooperates with a spiral cam 11 on the thermostat connecting member 41: This cam extends only 180 and the pin 43 is assembled so that the ledge 16 does not engage the cam during normal operation through the full adjustment range, as previously described. However, when the temperature control adjustment is turned through a further 180 in thedirection indicated by the arrows in Fig. 1, the ridge 16 engages the spiral cam 11 and raises the xpansible element 35, valve lifter 29, valve member 30, and valve spring 32 whereby the tab 15 operates the trigger 1| to release member 64, as previously described, which allows the valve member 65 to snap closed under the action of the U-shaped spring 69. The adjusting pin 43 i provided with a flat side 18 which cooperates with a corresponding flat side of the aperture through the cap member 44 whereby these parts may be assembled in only one position. The cap member 44 of the temperature control adjustment is provided with a lug 19 which cooperates with a' stop on the cover plate 23 to prevent turning of the temperature control adjustment which position the valve 65 is open. This valve will be referred to as the defrosting valve, whereas the valve 30 is known as the temperature control valve, or merely control valve. The expansible element 8| is connected by a capillary tube 83 and a T 84 to the capillary tube 31 with the sensitive bulb 38 on the evaporator l5. It will be understood, however, from the following description of operation that a separate bulb 38a and capilliary tube connection 83a may be provided for the expansible element 8|, as illustrated in Fig. 8, without changing the result. With the first arrangement however, only one capillary tube is required between the evapo-. rator in the storage compartment and the control device in the lower apparatus compartment of the refrigerator.

In order to provide a minimum flow of gas to the burner for maintaining a pilot flame when either or both of the valves are closed, there is provided a by-pass conduit comprisingpassages 85, 86, 81 and 88, as best seen in Fig. 5. The by-passed flow of gas from passage 86 into passage 87 is adjusted by a screw type needle valve not shown in Fig. 5, but which is threaded from the exterior into passage 86 which is then closed by a cap screw 89, as shown in Fig. 1. Since the burner I8 is provided with a thermostatic safety device 90, of a type well known in the art, for cutting off the supply of gas to the burner when the flame is extinguished, there is also provided a burner lighter tube 9| controlled by a normally closed manually operated push valve 92. As may be seen in Fig. 5, gas is admitted to the burner lighter valve through a passage 93 from valve chamber 34.

In operation, the gas burner I8 is lighted b opening valve 92 and igniting the gas which issues from the end of the burner lighter tube 9|. If the operation is being started for'the first time, the evaporator will be at substantially room temperature, wherefore both expansible elements 35 and 8| of the control device 2| will be expanded and valves 39 and 65 will be open. Upon heating of the thermostatic safety valve 9|], the latter opens and gas will be admitted to the burner |8 which will become ignited from the flame at the end of the burner lighter tube 9|, whereupon the burner lighter valve 92 may be released. After operation of the refrigeration apparatus for a suficient length of time, the temperature of evaporator will decrease. At a predetermined temperature, the expansible element 8| contracts, that is, the diaphragm 82 snaps inwardly, leaving the defrosting valve lever 64 detained in the open valve position by the trigger 1|. I8, and therefore the operation of the refrigeration apparatus is controlled by the temperature.

control valve 39 which is operated by the exansible element 35 responsiveto the temperature of the cooling element l5 to maintain the latter at a substantially constant value. Turning the control knob 52 on the front of the evaporator l5 over the lower half of the scale varies the adjustment of the control thermostat, as previously described, and thereby varies the temperature at which the evaporator or cooling element I5 will be maintained.

After a further period of operation it will become desirable toremove the frost formation from the evaporator l5, that is, defrost the evaporator. To accomplish this, the control knob 52 on the front of the evaporator I5 is turned clockwise, as indicated by the arrow, to the position marked Defrost- Movement in this direction is.

limited by the lug I9 contacting the stop 88 on the control device 2|, as previously described. The control'knob52 may then be turned back immediately to the setting at which it is desired' the apparatus should operate following the defrosting period. In turning the control knob to the defros position, the ledge 18 on the adjustment pin 43 of the control device engages the spiral cam 11 on the connecting member 41 thereby shifting the expansible element 35, valve lifter 29, valve member 30 and valve spring 32 an abnormal distance, and the trigger H is swung clockwise, as seen inFig. 4, by the downturned lug I5 onthe valve spring32 to release the defrosting valve lever 64, whereupon the defrosting valve 65 is snapped closed by the U- shaped spring 69, cutting off the supply of gas to the burner .|8 except for that which flows through the by-pass, as previously described, to maintain a minimum pilot flame. The operation of the refrigeration apparatus being interrupted, the temperature of the evaporator l5.

will rise to the melting point of the frost coating thereon, whereupon the latter will melt and drop into a suitable-receptacle, not shown, positioned beneath the evaporator for this purpose. The expansible element 8| is so designed that upon increase in temperature of the evaporator to the melting point of the frost, the pressure therein increases sufficiently to snap the diaphragm 82 outwardly, thereby opening the defrosting valve 95 and moving the valve lever 64 into such'position that it is caught and retained by the projection 13 of the trigger 1|, as previously described. Flow of gas to the burner I8 is again resumed and operation of the refrigeration apparatus under control of the thermostatic control valve 38 occurs and the temperature of the evaporator I5 is again decreased to a value determined by the setting of the control knob 52 which was made upon instigation of the defrosting period.

In Fig. '7 there is shown a portion of the control device 2| in, a sectional view similar to Fig. 4

, illustrating a modification of the arrangement The flow of gas to the burner for instigating the defrosting period by shifting the expansible thermostatic element 35. In this modification, the sleeve 42 of the adjustment assembly is provided with an ordinary pin or rod 94 which is reciprocable in the sleeve and has a plain rounded end which forms the abutment for the connecting member 41 of the thermostat. A grooved pulley 95 secured on the sleeve 42 by a set screw 96 is similar to the pulley 50 previously described in connection with Fig. 4 except that the pulley 95 has a hub extension 91 which closes the end of the sleeve 42 and serves as an abutment for the end of the pin 94. There is provided a flexible wire or similar element 98 in a flexible tube or casing 99. One end of the flexible wire 98is connected to a push button I00 and the other end extends through an opening |0| 'of the evaporator l5.

in the pulley hub extension 9'! and is seated in a socket H12 in the end of the adjustment pin 94. The push button Hill is reciprocable in a casing I03 which may be suitably located for ready access by the user as, for instance, on the front One end of the flexible tube 99 is secured to the push button casing I03 and the other end is provided with a flanged member I04 which is secured against substantial axial movement with respect to the pulley hub extension 91 by a retaining ring 105 threaded on the latter. The retaining ring N35 is so designed as to allow rotation of the pulley independently of the flanged member I64 except for a possible slight amount of friction which is substantially constant and therefore unobjectionable. The push button I is biased to its position shown in Fig. 7 by a coil spring I06 in the push button housing I03. To instigate a defrosting period, the push button is manually depressed.

This movement of the push button is transmitted by the flexible wire 98 to the pin 94 which shifts the connecting member 41 and expansible elementto operate the defrosting valve in the manner previously described. When the push button I00 is released, the parts return to their normal position under the action of the spring W6 and at the end of the defrosting period, operation of the refrigeration apparatus will be resumed, as previously described, to produce reirigeration at the temperature for which the temperature control adjustment described above may be set. In this modification, the temperature adjustment need not be disturbed to efiect defrosting.

It will be apparent to those skilled in the art that various other changes may be made in the construction and arrangement without departing from the spirit of the invention, and therefore the invention is not limited to that which is described in the specification and shown in the drawings, but only as indicated in the following claims.

What is claimed is:

1. In mechanism of the character described, a control member, an element responsive to temperature to normally operate said control member, a part movable between definite limits to impart movement to said element to adjust the tion of said control member, the ratio of movements of said part and said element being substantially constant between said definite limits, and structure interposed between said part and said element to vary the substantially constant ratio of movements of said element and said part when the latter is moved beyond said definite limits.

2. In mechanism of the character described, a control member, an element to operate said control member, a part movable between definite limits to impart movement to said element, the ratio of movements of said element to said part being substantially constant between said definite limits, and means associated with said part and said element wherebythe ratio of the movements of said element to said part is increased above said constant ratio when said part is moved beyond said definite limits.

3. In valve mechanism of the character described, a valve, a thermostat element to operate said valve, a threaded screw axially movable by rotation thereof to adjust the position of said when thermostat element, and means between said screw and said thermostat element whereby the latter is moved a greater distance than the axial movement of said screw for a part of a revolution of said screw.

4. In valve mechanism of the character described, a valve, a thermostat element to operate said valve,-a threaded screw axially movable by rotation thereof to adjust the position of said thermostat element, and a cam between said screw and said thermostat element arranged to move the latter a greater distance than the axial movement of said screw for a part of a revolution of said screw.

5. In valve mechanism of the character described, a valve, a thermostat element to operate said valve, a resilient diaphragm upon which said thermostat element is mounted and bodily movable therewith, a threaded screw axially movable by rotation thereof to move said diaphragm andadjust the position of said thermostat element, and means interposed between said screw and said diaphragm and arranged to move the latter a greater distance than the axial movement of said screw for a part of a revolution of said screw.

6. In valve mechanism of the character described, a valve, an expansible thermostat element tooperate said valve, a resilient diaphragm having an open n a hub member having an opening and secured to said diaphragm at the opening in the latter, said expansible thermostat element being secured to said hub member and communicating with the opening therein, a threaded screw axially movable by rotation thereof to move said diaphragm and adjust the position of said expansible thermostat element, and means interposed between said screw and said diaphragm to move the latter a greater distance than the axial movement of said screw for a part of a revolution of said screw.

7. In valve mechanism of the character described, a valve, a thermostat element to operate said valve, a member movable to impart movement to said thermostat element, and structure so constructed and arranged that it does not afiect the ratio of the movements of said thermostat element and said member in one range of movement of said member and comes into play in another range of movement of said member to vary the ratio of the movements of said thermostat element and said member.

8. In valve mechanism of the character described, a valve, an element responsive to temperature to operate said valve, a member movable to impart movement to said element, and

structure so constructed and arranged that the ratio of the movements of said element to said member is substantially constant in one range of movement of said member and progressively different with successive increments of movement of said member beyond said range.

9. In mechanism of the character described, a control member, an element responsive to temperature to operate said control member, a part movable to impart movement to said element, and a cam so constructed and arranged that it does not affect the ratio of the movements of said element and said part in one range of movement of said part and comes into play in another range of movement of said part to vary the ratio of the movements of said element and said part.

SVEN W. E. ANDERSSON. 

